:root{
            --safe-primary:#0b5fff;
            --safe-primary-dark:#0847c4;
            --safe-accent:#00d4aa;
            --safe-dark:#0d1b2a;
            --safe-darker:#08111c;
            --safe-text:#1f2937;
            --safe-muted:#5b6b7c;
            --safe-bg:#ffffff;
            --safe-bg-alt:#f5f8ff;
            --safe-border:#e6ecf5;
            --safe-radius:20px;
            --safe-shadow:0 12px 30px rgba(11,95,255,.08);
            --safe-transition:.3s cubic-bezier(.4,0,.2,1);
            --font-sans:'Inter','PingFang SC','Microsoft YaHei','Segoe UI',sans-serif;
            /* FAQ页面额外变量 */
            --faq-accent:#0891b2;
            --faq-accent-light:#e0f2fe;
            --faq-gradient:linear-gradient(135deg,#0d1b2a 0%,#164e63 100%);
        }
        *{margin:0;padding:0;box-sizing:border-box}
        html{scroll-behavior:smooth}
        body{font-family:var(--font-sans);color:var(--safe-text);background:var(--safe-bg);line-height:1.6;overflow-x:hidden}
        a{text-decoration:none;color:inherit}
        img{max-width:100%;display:block}
        .site{display:flex;flex-direction:column;min-height:100vh}
        .section-wrap{max-width:1200px;margin:0 auto;padding:0 24px}

        /* Header (与首页一致，包含网站地图链接) */
        .site-header{background:rgba(255,255,255,.9);backdrop-filter:blur(12px);position:sticky;top:0;z-index:100;border-bottom:1px solid var(--safe-border)}
        .nav-shell{display:flex;align-items:center;justify-content:space-between;max-width:1200px;margin:0 auto;padding:12px 24px;gap:20px}
        .brand{display:flex;align-items:center;gap:8px;font-weight:800;font-size:1.5rem;color:var(--safe-dark);}
        .brand img{height:40px;width:auto}
        .main-nav{display:flex;align-items:center;gap:28px}
        .main-nav a{font-weight:600;color:var(--safe-text);position:relative;padding:6px 0;transition:var(--safe-transition)}
        .main-nav a::after{content:"";position:absolute;left:0;bottom:0;width:0;height:2px;background:var(--safe-primary);transition:var(--safe-transition)}
        .main-nav a:hover::after,.main-nav a.active::after{width:100%}
        .main-nav a.active{color:var(--safe-primary)}
        .menu-button{display:none;background:none;border:none;cursor:pointer;width:32px;height:32px;flex-direction:column;justify-content:center;gap:5px}
        .menu-button span{display:block;width:22px;height:2px;background:var(--safe-text);border-radius:2px;transition:var(--safe-transition)}

        /* 通用按钮样式（确保边框正常） */
        .download-buttons{display:flex;flex-wrap:wrap;gap:14px}
        .download-button{
            display:inline-flex;
            align-items:center;
            justify-content:center;
            gap:8px;
            font-weight:600;
            padding:12px 22px;
            border-radius:50px;
            border:1.5px solid transparent;
            transition:var(--safe-transition);
            box-shadow:0 8px 20px rgba(13,27,42,.15);
            cursor:pointer;
            text-align:center;
        }
        .download-button:hover{
            transform:translateY(-2px);
            box-shadow:0 12px 24px rgba(11,95,255,.25);
        }

        /* FAQ Hero 区域 */
        .faq-hero{background:var(--faq-gradient);color:#fff;padding:80px 0 70px;position:relative;overflow:hidden}
        .faq-hero::before{content:"";position:absolute;top:-20%;right:-10%;width:500px;height:500px;background:radial-gradient(circle,rgba(8,145,178,.25) 0%,transparent 70%);border-radius:50%;pointer-events:none}
        .faq-hero::after{content:"";position:absolute;bottom:-30%;left:-10%;width:400px;height:400px;background:radial-gradient(circle,rgba(0,212,170,.15) 0%,transparent 70%);border-radius:50%;pointer-events:none}
        .faq-hero-grid{display:grid;grid-template-columns:1.1fr .9fr;gap:50px;align-items:center;position:relative;z-index:2}
        .faq-hero-kicker{display:inline-block;background:rgba(255,255,255,.1);backdrop-filter:blur(8px);color:#a5f3fc;font-weight:700;font-size:14px;padding:8px 18px;border-radius:40px;margin-bottom:18px;letter-spacing:.5px}
        .faq-hero-heading{font-size:clamp(2.2rem,4.5vw,3.4rem);line-height:1.2;font-weight:800;margin-bottom:20px}
        .faq-hero-heading span{color:var(--safe-accent)}
        .faq-hero-text{font-size:1.15rem;color:rgba(255,255,255,.85);max-width:560px;margin-bottom:30px}
        .faq-hero-media img{border-radius:24px;box-shadow:0 30px 60px rgba(0,0,0,.3)}

        /* 快捷导航卡片 */
        .quick-nav{padding:70px 0 0;background:var(--safe-bg)}
        .quick-nav .section-wrap{display:grid;grid-template-columns:repeat(auto-fit,minmax(200px,1fr));gap:20px}
        .quick-card{background:var(--safe-bg-alt);border:1px solid var(--safe-border);border-radius:16px;padding:24px 20px;text-align:center;transition:var(--safe-transition)}
        .quick-card:hover{transform:translateY(-4px);box-shadow:var(--safe-shadow);border-color:var(--faq-accent)}
        .quick-icon{font-size:2rem;margin-bottom:10px}
        .quick-card h3{font-size:1.1rem;font-weight:700;color:var(--safe-dark)}

        /* 安装步骤时间线 */
        .install-section{padding:80px 0;background:var(--safe-bg)}
        .install-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .install-tabs{display:flex;justify-content:center;gap:12px;margin-bottom:40px;flex-wrap:wrap}
        .install-tab{padding:10px 24px;border-radius:40px;border:1px solid var(--safe-border);background:var(--safe-bg-alt);font-weight:600;cursor:pointer;transition:var(--safe-transition)}
        .install-tab.active{background:var(--faq-accent);color:#fff;border-color:var(--faq-accent)}
        .install-panel{display:none;max-width:800px;margin:0 auto}
        .install-panel.active{display:block}
        .step-list{list-style:none;counter-reset:step}
        .step-list li{display:flex;gap:16px;align-items:flex-start;margin-bottom:24px;background:#fff;border:1px solid var(--safe-border);border-radius:12px;padding:20px}
        .step-num{width:36px;height:36px;border-radius:50%;background:var(--faq-accent-light);color:var(--faq-accent);display:flex;align-items:center;justify-content:center;font-weight:800;flex-shrink:0}
        .step-content h3{font-size:1.1rem;font-weight:700;color:var(--safe-dark);margin-bottom:6px}
        .step-content p{color:var(--safe-muted);font-size:.95rem}

        /* 多端同步机制 */
        .sync-mechanism{padding:80px 0;background:var(--safe-bg-alt)}
        .sync-mechanism h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:20px}
        .sync-mechanism .subtitle{text-align:center;color:var(--safe-muted);max-width:700px;margin:0 auto 50px;font-size:1.05rem}
        .sync-flow{display:flex;flex-wrap:wrap;justify-content:center;align-items:center;gap:20px}
        .sync-node{background:#fff;border:1px solid var(--safe-border);border-radius:16px;padding:20px 24px;text-align:center;min-width:140px;transition:var(--safe-transition)}
        .sync-node:hover{transform:translateY(-4px);box-shadow:var(--safe-shadow)}
        .sync-node-icon{font-size:2rem;margin-bottom:8px}
        .sync-arrow{font-size:2rem;color:var(--faq-accent)}
        .sync-center{background:var(--faq-accent);color:#fff;border-radius:16px;padding:20px 24px;text-align:center;min-width:160px}
        .sync-center h3{color:#fff;font-size:1.1rem}

        /* 账号管理卡片 */
        .account-section{padding:80px 0;background:var(--safe-bg)}
        .account-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .account-grid{display:grid;grid-template-columns:repeat(auto-fit,minmax(240px,1fr));gap:28px}
        .account-card{background:var(--safe-bg-alt);border-radius:var(--safe-radius);padding:28px 22px;text-align:center;border:1px solid var(--safe-border);transition:var(--safe-transition)}
        .account-card:hover{transform:translateY(-5px);box-shadow:var(--safe-shadow)}
        .account-icon{font-size:2.5rem;margin-bottom:14px}
        .account-card h3{font-size:1.2rem;font-weight:700;color:var(--safe-dark);margin-bottom:8px}
        .account-card p{color:var(--safe-muted);font-size:.9rem}

        /* 聊天记录迁移提示 */
        .migration-section{padding:80px 0;background:var(--safe-bg-alt)}
        .migration-section .section-wrap{max-width:900px}
        .migration-banner{background:linear-gradient(135deg,var(--safe-dark) 0%,#1e3a5f 100%);border-radius:24px;padding:40px 32px;color:#fff;display:flex;flex-direction:column;gap:20px;align-items:center;text-align:center}
        .migration-banner h2{font-size:clamp(1.6rem,3vw,2.2rem);font-weight:800}
        .migration-banner p{color:rgba(255,255,255,.8);max-width:600px}

        /* FAQ 手风琴列表 */
        .faq-list-section{padding:80px 0;background:var(--safe-bg)}
        .faq-list-section h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;color:var(--safe-dark);text-align:center;margin-bottom:50px}
        .faq-list{max-width:800px;margin:0 auto}
        .faq-item{border-bottom:1px solid var(--safe-border);padding:20px 0}
        .faq-question{font-weight:700;color:var(--safe-dark);font-size:1.1rem;cursor:pointer;display:flex;justify-content:space-between;align-items:center;gap:20px}
        .faq-question::after{content:"+";font-size:1.5rem;color:var(--faq-accent);flex-shrink:0}
        .faq-answer{color:var(--safe-muted);margin-top:10px;display:none}
        .faq-item.active .faq-answer{display:block}
        .faq-item.active .faq-question::after{content:"−"}

        /* 底部提示 / CTA */
        .contact-cta{padding:80px 0;background:var(--faq-gradient);color:#fff}
        .contact-cta .section-wrap{text-align:center}
        .contact-cta h2{font-size:clamp(1.8rem,3.5vw,2.6rem);font-weight:800;margin-bottom:20px}
        .contact-cta p{color:rgba(255,255,255,.8);max-width:600px;margin:0 auto 30px}
        .contact-cta .download-buttons{justify-content:center}

        /* Footer (与首页一致) */
        .site-footer{background:var(--safe-darker);color:#aebdce;padding:60px 0 20px}
        .footer-wrap{max-width:1200px;margin:0 auto;padding:0 24px}
        .footer-logo{display:flex;align-items:center;gap:8px;font-weight:800;font-size:1.5rem;color:#fff;margin-bottom:32px;}
        .footer-logo img{height:40px;margin-bottom:0;}
        .footer-cols{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:32px;margin-bottom:40px}
        .footer-cols h2{font-size:1.1rem;font-weight:700;color:#fff;margin-bottom:16px}
        .footer-cols p{display:flex;flex-direction:column;gap:8px}
        .footer-cols a{color:#aebdce;transition:var(--safe-transition)}
        .footer-cols a:hover{color:var(--safe-primary)}
        .footer-cols .mail-link{color:var(--safe-accent)}
        .site-footer small{display:block;text-align:center;padding-top:20px;border-top:1px solid rgba(255,255,255,.08);color:#64748b;font-size:.85rem}

        /* Responsive */
        @media(max-width:900px){
            .faq-hero-grid{grid-template-columns:1fr;text-align:center}
            .faq-hero-text{margin-left:auto;margin-right:auto}
            .download-buttons{justify-content:center}
            .faq-hero-media img{margin:0 auto}
            .sync-flow{flex-direction:column}
            .sync-arrow{transform:rotate(90deg)}
        }
        @media(max-width:768px){
            .main-nav{display:none;position:absolute;top:64px;left:0;right:0;background:#fff;flex-direction:column;padding:20px;box-shadow:0 20px 40px rgba(0,0,0,.08);border-bottom:1px solid var(--safe-border);gap:12px}
            .main-nav.open{display:flex}
            .menu-button{display:flex}
            .nav-shell{flex-wrap:wrap}
        }